A juvenile black-crowned night heron standing on tree limb. At sunset, when most herons are flying toward their roosting places, the black-crowned herons are leaving the trees where they have spent the day scattering over the marshes to feed. By...

At sunset when most herons are flying toward their roosting places, the black-crowned night herons are leaving the trees where they have spent the day scattering over the marshes to feed. By foraging at night, these birds avoid competition with...

At sunset when most herons are flying toward their roosting places, the black-crowned night herons are leaving the trees where they have spent the day scattering over the marshes to feed. By foraging at night, these birds avoid competition with...

A Black-crowed Night-Heron guarding its nest and eggs while Finley and Bohlman capture a shot at Malheur lake in 1908. Malheur lake would later become a bird refuge in 1908 when President Roosevelt saw photography Finley and Bohlman did of that...

A hand painted glass slide by Finley and Bohlman of a Black-crowned night heron at a nest site in Malheur Lake, 1908. Finley and Bohlman photographs would later help Malheur become a bird refuge in 1908.

On 12-13 April 1988 a workshop on the analysis of avian population trends was held at the Patuxent Wildlife Research Center in Laurel, Maryland. The workshop was cosponsored by the Branch of Migratory Bird Research of the Patuxent Wildlife...